Construction Calculators

A construction calculator is a free online tool that estimates the amount of material a project needs — concrete, gravel, sand, bricks or lumber — based on the dimensions you enter, so you can order the right quantity before you start.

Most calculators multiply length by width by depth to find volume, then convert that volume into the unit materials are sold in, such as cubic yards, tons or bags, sometimes adding a weight or cost estimate.

Convert every measurement to feet, multiply length by width by depth to get cubic feet, then divide by 27. A 10 by 10 foot area at 6 inches deep is 10 × 10 × 0.5 = 50 cubic feet, or about 1.85 cubic yards.

Multiply the length of the space by its width, both in feet. A 12 by 15 foot room is 180 square feet. For irregular shapes, split the area into rectangles or triangles and add the parts together.

A waste allowance of 5 to 10 percent is typical for bulk materials like gravel, sand or topsoil. Cut materials such as bricks, tile or lumber often warrant 10 to 15 percent to cover offcuts and breakage.

They provide reliable estimates based on standard formulas and typical material densities, but actual requirements can vary with site conditions, moisture and supplier specifications, so confirm quantities before ordering.

Divide the total cubic feet by 27, since one cubic yard equals 27 cubic feet (3 ft × 3 ft × 3 ft).

Calculate the area in square feet, multiply by the depth in feet to get cubic feet, divide by 27 for cubic yards, then use the Gravel Calculator to convert to weight based on the gravel type you're using.

Multiply the slab or footing's length, width and thickness in feet to get cubic feet, divide by 27 for cubic yards, then use the Concrete Calculator to translate that into bags or ready-mix truck volume.

Volume equals length × width × depth for rectangular spaces, all measured in the same unit. Circular areas use π × radius² × depth instead.

Start with the Deck Material Calculator for boards, joists and fasteners, and use the Board Foot Calculator alongside it if you're pricing rough lumber by the board foot.

Yes, the calculators on this page accept both US customary units, such as feet and inches, and metric units, such as meters and centimeters.

Yes. The Mulch, Topsoil, Sand, Gravel and Aggregate calculators are all built for garden beds, paths, lawns and other landscaping work, not just structural building.

Yes, for most projects. Settling, uneven ground, offcuts and spillage mean the exact calculated amount usually falls short, so a 5 to 15 percent allowance is standard practice.